Alabama Cotton: Sorting Through New Dicamba Requirements

Photo: Debra L Ferguson Stock Photography

Photo: Debra L Ferguson Stock Photography

On October 27, EPA issued new labels for dicamba products Engenia, Xtendimax, and Tavium for use over-the-top in dicamba-tolerant crops. These new labels expire Dec 20, 2025. Major changes in the new labels include:

  1. Longer downwind buffer of 240 ft for open boom sprayers.
  2. Tank mixing drift reducing agents (DRA) and volatility reducing agents (VRA) are required when spraying over the top of tolerant crops.
  3. Federal cut off dates for applications in cotton and soybean (cotton July 30; soybean June 30 or R1, whichever occurs first).
  4. Reduced downwind buffer with hooded/shielded sprayers (110 ft between last treated row to the closest downwind field edge).
  5. Mandatory training every other year for all applicators, and these products remain as restricted use pesticides. Other requirements remain similar to the old labels.

I am not too surprised by the new requirements since I have spent a lot of time working on dicamba research which led to some of these label changes. On the one hand, I feel growers’ pain about more restrictions. On the other, new requirements in federal labels are needed to minimize dicamba drift and off-target damage (especially for the Midwest and Midsouth). Otherwise, it could be expected that the Ninth Circuit could ban these labels again very soon. There needs to be a balance between these two sides so we can still use the technology and products in the future.

Two thoughts I want to mention. First, additional downwind buffer requirements are definitely not user friendly for AL and the rest of the Southeast. Our fields are usually small and irregular in shape. The 240 ft downwind buffer can take away a large portion of our fields, and Palmer amaranth will thrive in these unsprayed areas. Secondly, the situation with VRA is still uncertain. In 2019 and 2020, researchers have suggested that more VRAs — due to their strong efficacy to reduce volatility — should be included in future applications with manufacturers covering the cost.

It is unclear at this point whether manufacturers will provide VRAs as a co-pack or not. I personally prefer that more VRAs be built into product formulations, but that is not always possible due to technical difficulties, storage, and transportation. I am also expecting third-party VRAs being approved like other spray adjuvants, with information provided through the product websites. I will keep growers updated about VRA requirements.
In a nutshell, I am glad we have dicamba back as a weed management tool, and I appreciate EPA’s decision given the tremendous pressure they faced. Mandatory training is still required for all users. Details of AL dicamba training for 2021 will be determined soon. There will be online training options due to the COVID situation, and possibly a few small scale, in-person trainings in a socially distanced fashion. More details will follow in the next month or so.
My program is still working on analyzing data from our 2020 trials. Results of trials that address important weed control issues will be available for cotton growers early next spring. These include glyphosate-dicamba antagonism, cover crop effects, pigweed removal, weed control demonstrations, dicamba volatility reduction, etc. Meanwhile, over 100 populations of pigweed, goosegrass, and sicklepod have been collected for herbicide tolerance and resistance screening from over 20 row crop counties in AL. Please contact me at 334-707-7370 for any questions or concerns.

Source URL: